Mukhtasar Bukhari

Narrated from Ummul Momineen Maimunah bint Al-Harith (may Allah be pleased with her) that she freed one of her slave girls without seeking permission from the Prophet (peace and blessings be upon him). Then, when it was her turn (the day when the Prophet would stay with her), she said, "Do you know that I have freed my slave girl?" The Prophet (peace and blessings be upon him) said, "Have you really freed her?" She replied, "Yes." The Prophet (peace and blessings be upon him) said, "If you had given her to your maternal relatives, you would have obtained more reward in that."